Marc Malkin

Madonna humped Justin Timberlake.

And I got to see it. Timberlake was the surprise guest at Madge’s one-night only show at New York's Roseland Ballroom tonight, and the chemistry between the two was hot as they were humping, bumping and grinding through "4 Minutes."

Despite the fact that she's old enough to be his mother, they really do make beautiful music together.

She mostly stuck to songs off the new disc Hard Candy, but the evening—including a laser light show—had a totally '80s feel to it.

Madonna's tracksuit had that vintage look (even though it was new Dolce & Gabbana). The backup dancers were practically break-dancing. And J.T. reeled off some of his best Michael Jackson-inspired moves.

There were a couple of glitches. Read on for those.

During “Hung Up,” one of only two older songs she performed in her seven-song set, the vocal track skipped a couple beats, which left her looking a little flustered.

Then at the end of that same song, Madonna fell on her butt. Even with all the energetic gyrations onstage, I’m pretty sure she didn’t mean to do that.